Brain Abscesses of Ear, Nose, and Throat Origin: Comparison between Otogenic and Sinogenic Etiologies

Abstract

This retrospective study analyzed 29 cerebral abscesses of ear, nose, and throat (ENT) origin. The mean follow-up of patients was 37 months. ENT etiologies included 45% otitis media (n = 13), 48% sinusitis (n = 14), and 7% ethmoidal sinus tumors (n = 2). Thirty-eight percent (n = 5) of otogenic abscesses occurred within 15 days after a mastoidectomy. Sinogenic abscesses were never due to surgery but were associated in 31% of cases (n = 5) with anterior skull base defects. The main locations of otogenic abscesses were the temporal lobe (54%; n = 7) and the cerebellum (23%; n = 3), whereas sinogenic abscesses were located in the frontal lobe in 75% of cases (n = 12). Because of this location, sinogenic abscesses were less symptomatic than otogenic ones and had greater size and encapsulation at the time of diagnosis. Thus, they required longer antibiotic treatment (p = 0.05) and more numerous surgical drainages (p = 0.02). Bacteriologic abscesses samples were positive in 90% of cases. Bacteria found in brain abscesses were different from the ones found in ENT samples in 62% of cases. Thus, the results of ENT bacteriologic samples were not helpful for choosing adequate antibiotic agents in case of negative brain abscess samples. Although mortality was not significantly higher in otogenic abscesses (31%; n = 4) than in sinogenic ones (6%; n = 1, p = 0.08), otogenic abscesses appeared more threatening. Indeed, they represented 80% (n = 4) of lethal cases and encompassed more clinical or radiological prognosis pejorative factors than sinogenic ones (p = 0.006). In conclusion, higher danger of otogenic abscesses mainly resulted both from their temporal or cerebellous locations and from the bacteria that were more frequently resistant to antibiotics.